Add tasks for all the new languages

Task/Short-circuit-evaluation/Sidef/short-circuit-evaluation.sidef

@@ -0,0 +1,16 @@
+func a(bool) { print 'A'; return bool }
+func b(bool) { print 'B'; return bool }
+ 
+# Test-driver
+func test() {
+    for op in ['&&', '||'] {
+        for x,y in [[1,1],[1,0],[0,1],[0,0]] {
+            "a(%s) %s b(%s): ".printf(x, op, y)
+            eval "a(Bool(x)) #{op} b(Bool(y))"
+            print "\n"
+        }
+    }
+}
+ 
+# Test and display
+test()